A pressure sensor using a magnetoresistance effect element can sense a pressure change by means of a change in the angle between the magnetization of a magnetization free layer and the magnetization of a reference layer. In such a pressure sensor, an external magnetic field such as the geomagnetic field may influence at least one of the magnetization of the magnetization free layer and the magnetization of the reference layer as external noise.
In personal digital assistants etc. in which a microphone including a pressure sensor using a magnetoresistance effect element is installed, there is a case where the microphone is provided in a position relatively close to a loudspeaker because of the downsizing of the arrangement space etc. Consequently, audio signals may be fed back and echoes may occur.